Time Course by Substance: Source-Verified Descriptions

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This page reports how long effects were observed to last in published research and on a regulator label. It is a description only. It is not a schedule, and it gives no guidance on when to take, repeat, combine or "intensify" anything. Durations vary a great deal between people, and they depend on the substance, the form, the amount and the route. A duration measured in one study is not a promise for anyone else.

If someone needs urgent help, call 911 (US). US Poison Help is 1-800-222-1222 (see poison help by country).

Evidence labels used here: approved medicine (regulator and indication named), established (measured in controlled studies), insufficient evidence (one small study) and Proper evidence not found where we looked and found nothing usable.

Summary table

Psilocybin

In a double-blind placebo-controlled crossover study of 28 healthy people, "any drug effect" was modeled from ratings. Average effect duration was 5.6 hours at the lower study amount and 6.5 hours at the higher, with individual ranges of about 2.5 to 10 and 3.7 to 12 hours. Time to maximal effect was about 2 hours and time to onset about 0.8 hours. [1] The study was done with purified psilocybin in capsules (99.7% purity). [1] The authors write that effect duration was dose-dependent, with higher amounts producing longer effects. [1] Label: established for purified psilocybin in healthy volunteers. Proper evidence not found here for how long effects last with mushrooms or mushroom products, because no source we read measured that; content of such products varies and cannot be assumed. See psilocybin mushrooms and truffles.

LSD

The same 28-person study found LSD's effects clearly longer than psilocybin's, with an earlier onset. The authors explain the difference in duration by pharmacokinetics (how the body clears the compound): average elimination half-lives were about 4 hours for LSD and 2.5 hours for psilocin, the active form made from psilocybin. [1][2] A separate 16-person study found average duration of subjective effects rose from 6.7 to 11 hours as the study amount increased across the range tested. [3] Label: established for controlled laboratory administration. See LSD.

MDMA

NIDA, describing non-clinical use of MDMA, says effects may be felt within about 45 minutes, peak within 15 to 30 minutes, and last an average of three hours. [4] These are general NIDA descriptions and not clinical trial protocols. MDMA is not a classic psychedelic. See MDMA.

Ayahuasca and DMT are not the same

• Ayahuasca. In a placebo-controlled trial of 18 volunteers who had used psychedelics before, encapsulated freeze-dried ayahuasca produced subjective effects peaking between 1.5 and 2 hours, and the peak of DMT in blood coincided with them. [5] It is not the traditional brew, and this lab form says little about ceremonial practice. See ayahuasca.
• Intravenous DMT. In 12 experienced users given IV DMT, effects began almost immediately, peaked at 90 to 120 seconds and were almost completely resolved by 30 minutes. [6] Another report from the same research found peak blood levels and subjective effects within 2 minutes and negligible levels at 30 minutes. [8] Label: insufficient evidence to generalize beyond this 1994 intravenous research setting; it does not describe how DMT acts by other routes. See DMT.

Ketamine and esketamine

Label (esketamine): approved medicine (US FDA; treatment-resistant depression in adults, and depressive symptoms in adults with major depressive disorder and acute suicidal ideation or behavior). Blood pressure increases peak about 40 minutes after use and last about 4 hours. Dissociation was transient and occurred on the day of dosing. [7] Patients are monitored by a healthcare provider for at least 2 hours, and are told not to drive until the next day after a restful sleep. [7] For ketamine as a non-approved use, proper evidence not found here for a single duration: the NIDA ketamine page we read lists side effects but does not give a time course. [9] See esketamine and ketamine.

Other substances

We did not read source-verified time-course data for 5-MeO-DMT, ibogaine or iboga, salvia, Amanita muscaria and other plants covered in this library. Proper evidence not found here; see their own pages through the Psychedelics & Psychoactive Research hub.

Why durations differ

Amount, formulation, route, individual body chemistry and health all matter. NIDA lists amount, potency, biology, age, sex, personality, mood, expectations, mindset and setting as factors. [10] Averages hide wide ranges (psilocybin's range above spans several hours). Do not use these figures to plan any activity, driving or work. NIDA warns that impaired thinking and perception can lead to injuries. [10] See impairment and accidents.